DNA Discovery Reveals Surprising Dolphin Origins

Summary

Until recently, scientists were not entirely sure what the origin of the clymene dolphin was. The researches noticed that it had some external features similar to a striped dolphin, but a skull structure that was similar to the spinner dolphin. It turns out that the clymene dolphin arose from both species. Although unlikely, hybrids of two separate species can survive and produce offspring. Some species can produce offspring but that offspring is infertile. For the offspring to be fertile and to eventually evolve into a distinct species, the hybrid must be very fit for the environment and it also must not mate with either parental species, but only other hybrids. To make this occurrence even more rare, dolphins are mammals, and mammals create fertile offspring more rarely than other groups such as fish or insects. In fact, the clymene dolphin is the first marine mammal, fertile hybrid ever identified. 

Connection

In the past unit we discussed hybrids, but only infertile ones. This article not only connects to the topic but also sheds more light on it, showing the circumstances in which the hybrid can be fertile and even evolve into a distinct and new species. The article also connects to the unit on genetics because of the method used to discover the origin of this dolphin species. The researchers compared the DNA of both the nucleus and the mitochondria. The mitochondrial DNA, as mentioned in the article, is received from just the mother. we also learned about this during the unit.

Author: Charles Q. Choi

Published: January 11, 2014

URL: http://news.nationalgeographic.com/news/2014/01/140111-hybrid-dolphin-species-ocean-animal-science/